package com.design.working.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebFilter("/*")
public class LoginFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
            throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String servletPath = request.getServletPath();
        String resourceType = servletPath.substring(1, (servletPath.indexOf("/", 1) == -1) ? 2 : servletPath.indexOf("/", 1));

        HttpSession session = request.getSession(false);
        if ("/index.jsp".equals(servletPath) || "/user".equals(servletPath) || "dist".equals(resourceType)
                || "images".equals(resourceType) || (session != null && session.getAttribute("username") != null)){
            filterChain.doFilter(request, response);
        } else {
            //request.getContextPath();为空
            response.sendRedirect(request.getContextPath() + "/index.jsp");
        }
    }

    @Override
    public void destroy() {

    }
}
